Plant Respiration and Climate Change Effects (original) (raw)
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Background Elevated levels of atmospheric [CO 2 ] are likely to enhance photosynthesis and plant growth, which, in turn, should result in increased specific and whole-plant respiration rates. However, a large body of literature has shown that specific respiration rates of plant tissues are often reduced when plants are exposed to, or grown at, high [CO 2 ] due to direct effects on enzymes and indirect effects derived from changes in the plant's chemical composition.
Plant Science, 2014
Our study sought to understand how past, low atmospheric CO 2 concentrations ([CO 2 ]) impact respiration (R) of soybean (Glycine max), when compared to plants grown under current and future [CO 2 ]s. Experiments were conducted using plants grown under 290, 400 and 700 ppm [CO 2 ]. Leaf R was measured in both darkness (R D ) and in the light (R L ; using the Kok method), with short-term changes in measurement [CO 2 ] and [O 2 ] being used to explore the relationship between light inhibition of leaf R and photorespiration. Root R, photosynthesis (A), leaf [N] and biomass allocation traits were also quantified. In contrast to the inhibitory effect of low growth [CO 2 ] on A, growth [CO 2 ] had no significant effect on leaf R D or root R. Irrespective of growth [CO 2 ], R L was always lower than R D , with light inhibiting leaf R by 17-47%. Importantly, the degree of light inhibition of leaf R was lowest in plants grown under low [CO 2 ], with variations in R L being positively correlated with R D and photorespiration. Irrespective of whether leaf R was measured in the light or dark, a greater proportion of the carbon fixed by leaf photosynthesis was released by leaf R in plants grown under low [CO 2 ] than under current/future [CO 2 ]'s. Collectively, our results highlight the differential responses of A and R to growth of plants under low to elevated atmospheric [CO 2 ].
Australian Journal of Botany, 1992
An analysis of elevated CO 2 effects (2-4 times ambient) on dark respiration rate and carbon content was undertaken for a wide range of plant species, using both published reports and new data. On average, leaf respiration per unit leaf area was slightly higher for plants grown at high CO 2 (16%), whereas a small decrease was found when respiration was expressed on a leaf weight basis (14%). For the few data on root respiration, no significant change due to high CO 2 could be detected. Carbon content of leaves and stem showed a small increase (1.2 and 1.7% respectively), whereas C-content of roots was not significantly affected. In both data sets direction of responses was variable. A sensitivity analysis of carbon budgets under elevated CO 2 identified changes in respiration rate, and to a lesser extent carbon content, as important factors affecting the growth response to elevated CO 2 in quite a number of cases. Any comprehensive analysis of growth responses to increased CO 2 should therefore include measurements of these two variables.
Does elevated atmospheric CO2concentration inhibit mitochondrial respiration in green plants?
Plant Cell and Environment, 1999
There is abundant evidence that a reduction in mitochondrial respiration of plants occurs when atmospheric CO 2 (C a) is increased. Recent reviews suggest that doubling the present C a will reduce the respiration rate [per unit dry weight (DW)] by 15 to 18%. The effect has two components: an immediate, reversible effect observed in leaves, stems, and roots of plants as well as soil microbes, and an irreversible effect which occurs as a consequence of growth in elevated C a and appears to be specific to C 3 species. The direct effect has been correlated with inhibition of certain respiratory enzymes, namely cytochromec-oxidase and succinate dehydrogenase, and the indirect or acclimation effect may be related to changes in tissue composition. Although no satisfactory mechanisms to explain these effects have been demonstrated, plausible mechanisms have been proposed and await experimental testing. These are carbamylation of proteins and direct inhibition of enzymes of respiration. A reduction of foliar respiration of 15% by doubling present ambient C a would represent 3 Gt of carbon per annum in the global carbon budget.
Does elevated atmospheric CO 2 concentration inhibit mitochondrial respiration in green plants?
Plant, Cell and Environment, 1999
There is abundant evidence that a reduction in mitochondrial respiration of plants occurs when atmospheric CO 2 (C a ) is increased. Recent reviews suggest that doubling the present C a will reduce the respiration rate [per unit dry weight (DW)] by 15 to 18%. The effect has two components: an immediate, reversible effect observed in leaves, stems, and roots of plants as well as soil microbes, and an irreversible effect which occurs as a consequence of growth in elevated C a and appears to be specific to C 3 species. The direct effect has been correlated with inhibition of certain respiratory enzymes, namely cytochromec-oxidase and succinate dehydrogenase, and the indirect or acclimation effect may be related to changes in tissue composition. Although no satisfactory mechanisms to explain these effects have been demonstrated, plausible mechanisms have been proposed and await experimental testing. These are carbamylation of proteins and direct inhibition of enzymes of respiration. A reduction of foliar respiration of 15% by doubling present ambient C a would represent 3 Gt of carbon per annum in the global carbon budget.
Apparent Reassimilation of Respiratory Carbon Dioxide by Different Plant Species
Physiologia Plantarum, 1967
Differences among species in respiration rates in CO2-free air, in light and dark, were studied using the standard leaf chamber technique and the infrared carbon dioxide analyzer. Photosynthesis, transpiration and respiration were measured. In all species studied, rates of respiration were considerably higher in dark than in light. This effect was assumed to be due to reassimilation of the respiratory CO2. A resistance analogy model was derived to account for the apparent differences in internal recycling of CO2 among species; the differences were correlated with differences in maximum photosynthetic rates in normal air and optimal conditions (P310) and with internal resistances to CO2 diffusion (rk). Species with high P310 and low rk appear to reassimilate all the endogenous CO2, whereas other species with lower P310 and higher rk appear to reassimilate only a part of their respiratory CO2.Experiments with the photosynthetic inhibitor, 3-(3,4-dichlorophcnyl)-l,l-dimethyl urea (DCMU), indicated that species with zero respiration in CO2-free air and light release respiratory CO2 when photosynthesis is inhibited. It is concluded that the CO2 released in the presence of DCMU represents respiratory CO2 which recycles to photosynthesis under normal conditions.
Implications of improved representations of plant respiration in a changing climate
Nature communications, 2017
Land-atmosphere exchanges influence atmospheric CO2. Emphasis has been on describing photosynthetic CO2 uptake, but less on respiration losses. New global datasets describe upper canopy dark respiration (R d) and temperature dependencies. This allows characterisation of baseline R d, instantaneous temperature responses and longer-term thermal acclimation effects. Here we show the global implications of these parameterisations with a global gridded land model. This model aggregates R d to whole-plant respiration R p, driven with meteorological forcings spanning uncertainty across climate change models. For pre-industrial estimates, new baseline R d increases R p and especially in the tropics. Compared to new baseline, revised instantaneous response decreases R p for mid-latitudes, while acclimation lowers this for the tropics with increases elsewhere. Under global warming, new R d estimates amplify modelled respiration increases, although partially lowered by acclimation. Future meas...
Plant Physiology, 2007
Studies on long-term effects of plants grown at elevated CO 2 are scarce and mechanisms of such responses are largely unknown. To gain mechanistic understanding on respiratory acclimation to elevated CO 2 , the Crassulacean acid metabolism Mediterranean invasive Opuntia ficus-indica Miller was grown at various CO 2 concentrations. Respiration rates, maximum activity of cytochrome c oxidase, and active mitochondrial number consistently decreased in plants grown at elevated CO 2 during the 9 months of the study when compared to ambient plants. Plant growth at elevated CO 2 also reduced cytochrome pathway activity, but increased the activity of the alternative pathway. Despite all these effects seen in plants grown at high CO 2 , the specific oxygen uptake rate per unit of active mitochondria was the same for plants grown at ambient and elevated CO 2. Although decreases in photorespiration activity have been pointed out as a factor contributing to the long-term acclimation of plant respiration to growth at elevated CO 2 , the homeostatic maintenance of specific respiratory rate per unit of mitochondria in response to high CO 2 suggests that photorespiratory activity may play a small role on the long-term acclimation of respiration to elevated CO 2. However, despite growth enhancement and as a result of the inhibition in cytochrome pathway activity by elevated CO 2 , total mitochondrial ATP production was decreased by plant growth at elevated CO 2 when compared to ambient-grown plants. Because plant growth at elevated CO 2 increased biomass but reduced respiratory machinery, activity, and ATP yields while maintaining O 2 consumption rates per unit of mitochondria, we suggest that acclimation to elevated CO 2 results from physiological adjustment of respiration to tissue ATP demand, which may not be entirely driven by nitrogen metabolism as previously suggested.